Dislocation and Elastic Strain in an InN Film Characterized by Synchrotron Radiation X-Ray Diffraction and Rutherford Backscattering/Channeling

Abstract

Dislocation information and strain-related tetragonal distortion as well as crystalline qualities of a 2-µm-thick InN film grown by molecular beam epitaxy (MBE) are characterized by Rutherford backscattering/channeling (RBS/C) and synchrotron radiation x-ray diffraction (SR-XRD). The minimum yield 𝜒min=2.5% deduced from the RBS/C results indicates a fairly good crystalline quality. From the SR-XRD results, we obtain the values of the screw and edge densities to be 𝜌screw = 7.0027 × 10 9 and 𝜌 edge = 8.6115 × 10 9 cm −2 , respectively. The tetragonal distortion of the sample is found to be −0.27% by angular scans, which is close to the −0.28% derived by SR-XRD. The value of |𝑒 ⊥ /𝑒 ‖ | = 0.6742 implies that the InN layer is much stiffer along the 𝑎 axis than that along the 𝑐 axis, where 𝑒 ‖ is the parallel elastic strain, and 𝑒 ⊥ is the perpendicular elastic strain. Photoluminescence results reveal a main peak of 0.653 eV with the linewidth of 60 meV, additional shoulder band could be due to impurities and related defects.